The DCP3925 Should be SPI Flash, In which case you can provided direct power to Flash in order to read and Program. Not sure if the TG862 is an SPI Flash, the TG822 IS and SPI Flash and there is no problem on Reading and Programming it by providing direct power to the Flash...........

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The DCP3925 Should be SPI Flash, In which case you can provided direct power to Flash in order to read and Program. Not sure if the TG862 is an SPI Flash, the TG822 IS and SPI Flash and there is no problem on Reading and Programming it by providing direct power to the Flash...........

You can try 3.3 Volts instead of 5Volts. And what SPI XML are you using as your target? The SPI flash should be 16MB so try DPC3000 as your target.

You may also need to add the SPI Flash to the "Flash XML"

I tested with 3.3v (4v) with DPC3000 XML, and also does not detect ... I checked all the welds and are 100%. The problem may be in USBJTAG? Some configuration? When I connect the power directly into the flash, I do not use the original 15v power supply of the modem. Is that correct?

I did a test with the external power with a multimeter. Disconnected, the external power is 3.3v, but connected directly in flash, drops to 1.65v. The 5v drops to 2v. This happened with a few different models of external power. Why does this happen? This may be the cause of the problem?

Do not have JTAG port. I'm already trying to use the SPI, but USBJTAG not detect the flash.

What value you have? If it is all00 or all ff you do not have it connect right.
If you use apply power on flash, you do not need to power on the modem. If you use ISP pin you must power on the modem.
Not all modem with power on flash will work. I found one modem that can detect flash even without the power and after apply power on it it flashes OK.

I did a test with the external power with a multimeter. Disconnected, the external power is 3.3v, but connected directly in flash, drops to 1.65v. The 5v drops to 2v. This happened with a few different models of external power. Why does this happen? This may be the cause of the problem?

What is the amp rating on the 5v external supply?
Can you lift VCC (pin2) from the pcb?
You are powering all the other components on the 3.3v rail, which is causing the voltage drop.

What value you have? If it is all00 or all ff you do not have it connect right.
If you use apply power on flash, you do not need to power on the modem. If you use ISP pin you must power on the modem.
Not all modem with power on flash will work. I found one modem that can detect flash even without the power and after apply power on it it flashes OK.

Quote:

Originally Posted by merkin

What is the amp rating on the 5v external supply?
Can you lift VCC (pin2) from the pcb?
You are powering all the other components on the 3.3v rail, which is causing the voltage drop.

The 5v external power used is a cell charger and has 800mha. I also tried with 5v of USB port of notebook, without success (ID 00 00 00).

When I lifted the pin 2 of the flash, the voltage did not drop, but the USBJTAGNT not yet detected the flash. For testing, I used also an BlackcatUSB (pin 2 up) and it worked perfectly with 3.3v and 5v. The connections are the same. What could be wrong with USBJTAGNT?

Note: In BlackcatUSB when pin 2 was lifted, worked perfectly. But when pin 2 was connected to the board, it does not work. If I use an 3.3v external power with higher amp, she will work with pin 2 connected to board?

I've been able to read and write to the 3925 spi using a blackcat and the nt with 3.3 volts.

Sometimes the length of the wire you have powering pin 1 can be the reason why you can't get a good detect, let alone a good read/write. I prefer to use a smaller one with a usb ttl and get the 3.3v off of that.

I've been able to read and write to the 3925 spi using a blackcat and the nt with 3.3 volts.

Sometimes the length of the wire you have powering pin 1 can be the reason why you can't get a good detect, let alone a good read/write. I prefer to use a smaller one with a usb ttl and get the 3.3v off of that.